Japanese scientists have discovered from experiments on mice that dreaming improves the supply of oxygen and refreshing nutrients to the brain, as well as improves the clearance of waste products from the brain.
Today it has been proven that many animals besides humans dream in their sleep.
Due to dreaming, the eyes moving in the closed eyelids of humans and animals are clearly visible in sleep, which can be used to detect the “sleeping state”.
In medical science, this rapid movement of the eyes (during sleep) is also called “Rapid Eye Movement” (REM) which is also a specific sign of sleep.
So far, research has shown that blood flow to the brain has been measured several times during waking, deep sleep, and during REM sleep, but the results of these studies have been very different and even contradictory.
To get better and more reliable results, scientists at the University of Suokuba and Kyoto in Japan used a state-of-the-art technique called “two-photon microscopy” to draw blood into the capillaries of mice. Directly photographed the flow.
For this purpose, they added a pigment and a harmless substance to the blood of mice, which also emits certain light during the chemical process. This substance began to circulate throughout the rat’s body, along with the blood.
During the experiments, the rats were allowed to sleep and wake up as usual, meaning they were not given any sedative or sleep-inducing drugs.
Modern microscopic imaging techniques showed that when the rats were in REM sleep, their brain blood flow was higher, while in deep sleep and wakefulness, the flow was normal.
“We were shocked by the results,” said Dr. Yu Hayashi, a lead author of the study and a professor at Tsukuba University. “During sleep, there was a tremendous flow of red blood cells in the capillaries of mice, which showed that this condition (sleep) is really very unique.”
Not only that, but when these rats were allowed to sleep again after waking up from a raw (sleepy) sleep, the blood flow to their brains increased more than before when the sleepy sleep resumed; This proves that there is a strong link between blood flow to the brain and sleep.
It should be noted that the blood that reaches the brain not only carries oxygen and nutrients there but also absorbs carbon dioxide and various waste products from the brain cells and expels them from the brain. And so it plays an important role in maintaining the health and well-being of the brain.
In the past, it was widely believed that blood flow to the brain was reduced during sleep, but recent research has disproved this notion.
The news published in the latest issue of the research journal “Cell Reports” is also a link in the same chain of experiments.